From the Guidelines
The safe rate of sodium reduction in hypernatremia is 10-15 mmol/L/24h.
Rationale
- This rate is recommended to avoid rapid correction of hypernatremia, which may induce cerebral oedema, seizures, and neurological injury 1.
- A more recent study suggests a similar rate of 8 mmol/L/day to avoid a decrease in serum sodium too quickly 1.
- It is essential to base therapeutic measures on the aetiology of hypernatremia, assessing the patient's intravascular volume and hydration status 1.
- In cases of symptomatic hypovolaemia, plasma volume should be replaced to ensure proper hydration and electrolyte balance 1.
- The administration rate may need to be adjusted based on the rate and composition of ongoing losses, replacing losses with a fluid containing a similar sodium concentration 1.
From the Research
Safe Rate of Sodium Reduction in Hypernatremia
The safe rate of sodium reduction in hypernatremia is a topic of ongoing research and debate. According to recent studies, the following points can be noted:
- A systematic review and meta-analysis found that faster correction rates (> 0.5 mmol/L per hour) showed no significant change in mortality, but subgroup analyses found significantly lower mortality with faster correction of hypernatremia at the time of hospital admission, within the first 24 hours of diagnosis, and for severe hypernatremia 2.
- Another study found that rapid correction of hypernatremia (> 0.5 mmol/L per hour) was not associated with a higher risk of mortality, seizure, alteration of consciousness, and/or cerebral edema in critically ill adult patients with either admission or hospital-acquired hypernatremia 3.
- A retrospective chart review of hospitalized patients with severe hypernatremia found that a slower correction rate of hypernatremia was associated with higher 30-day mortality, and that the recommended correction rate of ≤ 0.5 mEq/L/hr was not always followed 4.
- A review of hypernatremic disorders in the intensive care unit noted that the management of hypernatremia focuses on judicious replacement of free water deficit, and that the rate of correction depends on the rapidity of hypernatremia development, with frequent monitoring of plasma sodium levels essential to prevent cerebral edema from rapid correction of chronic hypernatremia 5.
- A study on correcting hypernatremia in children found that rapid correction (> 0.5 mmol/L per hour) was not associated with greater neurological investigation, cerebral edema, seizures, or mortality, but slow correction was associated with a longer hospital length of stay 6.
Key Findings
- Faster correction rates (> 0.5 mmol/L per hour) may be safe and beneficial in certain cases, such as severe hypernatremia or hypernatremia at the time of hospital admission.
- The recommended correction rate of ≤ 0.5 mEq/L/hr may not always be followed, and slower correction rates may be associated with higher mortality.
- Frequent monitoring of plasma sodium levels is essential to prevent cerebral edema from rapid correction of chronic hypernatremia.
- Rapid correction of hypernatremia is not associated with a higher risk of neurological complications or mortality in children.
Correction Rates
- The optimal correction rate for hypernatremia is still unclear, but recent studies suggest that faster correction rates may be safe in certain cases 2, 3, 6.
- The rate of correction should be individualized based on the patient's condition, with frequent monitoring of plasma sodium levels to prevent complications 5.